WO2014065189A1

WO2014065189A1 - Rare earth complex and application for same

Info

Publication number: WO2014065189A1
Application number: PCT/JP2013/078193
Authority: WO
Inventors: 上遠野　正孝
Original assignee: 株式会社クレハ
Priority date: 2012-10-24
Filing date: 2013-10-17
Publication date: 2014-05-01

Abstract

　The purpose of this invention is to provide a rare earth complex having superior light-resistance compared to europium complexes of the prior art, and to provide an application for said complex. This rare earth complex is a complex containing a rare earth element such as Eu, wherein a ligand (a) selected from a group of ligands represented by general formula (A) is coordinated to the rare earth element in an amount of 0.8-1.7 ligands per atom of rare earth element, a specific ligand (b) having a bipyridine skeleton or a phenanthroline skeleton is coordinated to the rare earth element in a quantity of 0.8-1.2 ligands per atom of the rare earth element, a specific ligand (c) having one diketonate structure in the ligand is coordinated to the rare earth element in a quantity of 0-1.4 ligands per atom of the rare earth element, and if the number of ligands (a) per atom of rare earth element is defined as α, and the number of ligands (c) is defined as γ, 2α + γ falls within the range of 3.0-3.4.

Description

Rare earth complex and use of the complex

The present invention relates to rare earth complexes and uses of the complexes.

Wind power, solar power, geothermal heat, etc. are attracting attention as clean energy sources that have no emissions that affect the environment. Solar cells capable of directly converting sunlight into electrical energy are a promising source of electrical energy and have been actively put into practical use in recent years.

Solar cells photoelectrically convert sunlight into electrical energy using photoelectric conversion materials, but the wavelength of light that can be effectively converted by photoelectric conversion materials is determined for each material, and other wavelengths are effective. It was not available.

Crystalline silicon solar cells using crystalline silicon as a photoelectric conversion material have been put into practical use as typical solar cells. However, crystalline silicon has low sensitivity to ultraviolet rays contained in a large amount of sunlight, and power generation efficiency is low. It was about 10 to 20%.

In order to improve the power generation efficiency of crystalline silicon solar cells, it has recently been proposed to convert the wavelength of ultraviolet light to 550 to 1000 nm, where crystalline silicon has high photoelectric conversion efficiency.
For example, a wavelength conversion type solar cell encapsulating sheet containing a fluorescent material having an absorption wavelength peak at 300 to 450 nm and an ultraviolet absorber is known (see, for example, Patent Document 1). In Patent Document 1, by providing the wavelength conversion type solar cell encapsulating sheet on the light receiving surface side of the solar cell, the wavelength of ultraviolet light contained in sunlight is converted, and the power generation efficiency of the solar cell is improved. The purpose of this sheet is to ensure the weather resistance of the sheet by containing an ultraviolet absorber.

Also, a fluorescent resin composition comprising an organic rare earth metal complex that emits fluorescence in the wavelength range of 550 to 900 nm and an ethylene-vinyl acetate copolymer is used as a sealant between the front cover and the crystalline silicon cell. A solar cell module has been proposed (see, for example, Patent Document 2). In patent document 2, the power generation efficiency of a solar cell is raised by using the said sealing agent.

Both the fluorescent substance disclosed in Patent Document 1 and the organic rare earth metal complex disclosed in Patent Document 2 have been proposed to use europium as a rare earth element.
However, the europium complexes disclosed in Patent Documents 1 and 2 cannot be said to have sufficient light resistance, and improvements have been desired from the viewpoint of long-term stability desired for solar cells.

JP 2011-210891 A International Publication No. 2008/047427 Pamphlet

The present invention has been made in view of the above prior art, and absorbs ultraviolet light to blue light, which can be used as a wavelength conversion sheet used as a constituent member of a solar cell module or the like, or as a sealant. An object of the present invention is to provide a rare earth complex that emits light and has light resistance superior to a conventionally known europium complex, and uses of the complex.

As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that a rare earth complex coordinated with a specific ligand is superior in light resistance to conventional complexes, and completed the present invention. .
That is, the rare earth complex of the present invention is a complex containing at least one kind of rare earth element selected from Pr, Eu, Sm, Tb, Dy, Ho, and Er, and includes the following general formula (A): At least one ligand (a) selected from the group of ligands represented by formula (1) is coordinated with 0.8 to 1.7 per rare earth element, and the rare earth element has the following general formula: At least one ligand (b) selected from the ligand group represented by (B) is coordinated 0.8 to 1.2 per rare earth element, At least one ligand (c) selected from the group of ligands represented by the following general formula (C) is coordinated with 0 to 1.4 per rare earth element, and the rare earth element 1 When the number of ligands (a) per unit is α and the number of the ligands (c) is γ, 2α Characterized in that γ is 3.0 to 3.4.

(In the ligand group represented by the general formula (A), X ¹ and X ² are each independently an aromatic ring, a heteroaromatic ring, —C (CH ₃ ) ₃ , —CH ₃ , —CF ₃ , — C ₂ F ₅ , —C ₃ F ₇ , or —C ₄ F _9. )

The rare earth complex preferably contains at least one rare earth element selected from Eu, Sm, and Tb.
The 2α + γ is preferably 3.0.

The resin composition of the present invention contains the rare earth complex and a resin.
The resin solution of the present invention contains the rare earth complex, a resin and a solvent.
The wavelength conversion sheet of this invention consists of the said resin composition.

The sealing agent of this invention consists of the said resin composition.
As one aspect | mode of the solar cell module of this invention, it has at least a photovoltaic cell and the said wavelength conversion sheet, The said wavelength conversion sheet is arrange | positioned at the light-receiving surface side of the said photovoltaic cell, It is characterized by the above-mentioned. .

As another aspect of the solar cell module of the present invention, the solar cell module has at least a solar cell, the sealant, and a front cover, and the sealant is interposed between the solar cell and the front cover. It is characterized by containing.

The rare earth complex of the present invention is a complex that absorbs ultraviolet light to blue light and emits light, and has light resistance superior to a conventionally known europium complex. For this reason, the rare earth complex of this invention can be used for the wavelength conversion sheet | seat and sealing agent which are structural members, such as a solar cell module.

Next, the present invention will be specifically described.
The rare earth complex of the present invention is a complex containing at least one rare earth element selected from Pr, Eu, Sm, Tb, Dy, Ho, and Er. The rare earth element is represented by the following general formula (A). At least one ligand (a) selected from the group of ligands coordinated with 0.8 to 1.7 per rare earth element, and the rare earth element has the following general formula (B At least one ligand (b) selected from the group of ligands represented by the following formula: At least one ligand (c) selected from the ligand group represented by the formula (C) is coordinated 0 to 1.4 per rare earth element, and per one rare earth element When the number of the ligands (a) is α and the number of the ligands (c) is γ, 2α + γ is 3. And wherein the ~ 3.4.

In the present invention, at least one ligand (a) selected from the ligand group represented by the general formula (A) is also simply referred to as a ligand (a), and the general formula (B) At least one ligand (b) selected from the represented ligand group is also simply referred to as ligand (b), and at least selected from the ligand group represented by the general formula (C). One type of ligand (c) is also simply referred to as ligand (c).

As described above, the rare earth complex of the present invention contains at least one rare earth element selected from Pr, Eu, Sm, Tb, Dy, Ho, and Er as the rare earth element.
The wavelength at which the rare earth complex is excited and the emission wavelength are mainly determined by the type of rare earth element. The rare earth element is preferable because it absorbs ultraviolet light to blue light, is excited, and crystal silicon emits light having a wavelength (550 to 1000 nm) having high photoelectric conversion efficiency as fluorescence.

Specifically, the excitation wavelength of Pr is 450 nm, the emission wavelength is 600 nm, 1250 to 1450 nm, the excitation wavelength of Eu is 330 to 430 nm, the emission wavelengths are 570 nm, 580 nm, 620 nm, and 630 nm. Excitation wavelengths are 360 nm and 410 nm, emission wavelengths are 560 nm, 610 nm, and 635 nm, excitation wavelengths of Tb are 200 to 350 nm, emission wavelengths are 490 nm, 550 nm, 590 nm, and 625 nm, and excitation wavelengths of Dy are 200 340 nm, emission wavelength 490 nm, 570 nm, 2400 nm, Ho excitation wavelength 380 nm, emission wavelength 620 nm, 2000 nm, Er excitation wavelength 400 nm, emission wavelength 610 nm, 970 nm, 1500-1600 A m.

The rare earth element is preferably at least one rare earth element selected from Eu, Sm and Tb from the viewpoint of wavelength conversion efficiency.
The rare earth complex of the present invention usually has 1 to 1000 rare earth elements per molecule, preferably 1 to 100, particularly preferably 1 to 10.

The rare earth complex of the present invention has the ligand (a) and the ligand (b), and optionally has a ligand (c).
The rare earth complex of the present invention has a ligand (a). The ligand (a) has two diketonate structures that are bidentate ligands in the ligand. That is, the ligand (a) is a bisdiketonate ligand. The present inventors have found that the rare earth complex of the present invention having a bisdiketonate ligand having a specific structure is excellent in light resistance as compared with conventionally known europium complexes. In addition, the rare earth complex of the present invention has sufficient emission characteristics.

In addition, as a result of intensive studies on the structure of the rare earth complex, the present inventors have found that the rare earth complex having the ligand (a) is sufficient when it does not have the ligand (b). It has been found that it does not have light resistance. In addition, the present inventors do not necessarily have excellent luminescent properties even in the case of a rare earth complex having a ligand (b) and a bisdiketonate ligand, but a specific bisdiketonate ligand, that is, a ligand. It has been found that the rare earth complex having (a) is excellent in emission characteristics.

In the ligand group represented by the general formula (A), X ¹ and X ² possessed by each ligand are each independently an aromatic ring, a heteroaromatic ring, —C (CH ₃ ) ₃ , —CH ₃ , —CF ₃ , —C ₂ F ₅ , —C ₃ F ₇ , or —C ₄ F ₉ .

X ¹ and X ² may be the same or different, and when a plurality of ligands (a) are present, each X ¹ and X ² may be the same or different.
Examples of the aromatic ring include a benzene ring, a naphthalene ring, and a biphenyl ring, and a benzene ring and a naphthalene ring are preferable.

Examples of the heteroaromatic ring include a thiophene ring, a furan ring, and a pyridine ring, and a thiophene ring is preferable.
X ¹ and X ² are preferably a heteroaromatic ring, —C (CH ₃ ) ₃ , —CH ₃ , —CF ₃ , and a heteroaromatic ring, —CF ₃ is preferably a high fluorescence quantum yield of the complex. Is more preferable from the viewpoint of the rate and emission intensity.

The at least one ligand (a) selected from the ligand group represented by the general formula (A) is at least selected from the ligand group represented by the general formula (A ′). It is preferable that it is a kind of ligand from a viewpoint of the light resistance of a complex, and a wavelength conversion characteristic.

(In the ligand group represented by the general formula (A '), X ¹ and X ² are the same as X ¹ and X ² in the general formula (A).)
The rare earth complex of the present invention has a ligand (b). The ligand (b) is a ligand having a bipyridine skeleton or a phenanthroline skeleton, and coordinates to a rare earth element as a bidentate ligand. The rare earth complex of the present invention having the ligand (b) is excellent in light resistance as compared with conventionally known europium complexes.

The at least one ligand (b) selected from the ligand group represented by the general formula (B) is at least selected from the ligand group represented by the general formula (B ′). A kind of ligand is preferable from the viewpoints of light emission intensity and light resistance.

The rare earth complex of the present invention may have a ligand (c). The ligand (c) has one diketonate structure which is a bidentate ligand in the ligand. That is, the ligand (c) is a diketonate ligand. In addition to the above-described ligand (a), the present inventors have obtained a rare earth complex having a light resistance higher than that of a conventionally known europium complex even when it has a diketonate ligand having a specific structure. It was found to be excellent in properties.

The at least one ligand (c) selected from the ligand group represented by the general formula (C) is at least selected from the ligand group represented by the general formula (C ′). A kind of ligand is preferable from the viewpoints of high fluorescence quantum yield and emission intensity.

In the rare earth complex of the present invention, the ligand (a) is coordinated in an amount of 0.8 to 1.7 per rare earth element. It is preferable that 0.8 to 1.2 or 1.3 to 1.7 of the ligand (a) is coordinated per rare earth element, 0.9 to 1.1, Alternatively, 1.4 to 1.6 coordination is more preferable, and 1.0 or 1.5 coordination is particularly preferable.

In the rare earth complex of the present invention, 0.8 to 1.2 ligands (b) are coordinated per rare earth element. The ligand (b) is preferably 0.9 to 1.1 coordinated per rare earth element, more preferably 1.0 coordinated.

In the rare earth complex of the present invention, 0 to 1.4 ligands (c) are coordinated per rare earth element. The ligand (c) is preferably coordinated with 0 to 0.4 or 0.6 to 1.4 per rare earth element, and is preferably 0 to 0.2 or 0.8. More preferably, 1.2 to 1.2 are coordinated, and 0 or 1.0 are particularly preferable.

In the rare earth complex of the present invention, 2α + γ is 3.0 to 3.4, where α is the number of ligands (a) per rare earth element and γ is the number of ligands (c). Preferably, it is 3.0 to 3.2, more preferably 3.0 to 3.1, and particularly preferably 3.0. The ligand (a) has two diketonate structures in the ligand, and the ligand (c) has one diketonate structure in the ligand, The 2α + γ indicates how many diketonate structures are coordinated with one rare earth element. That is, the rare earth complex of the present invention preferably has 3.0 to 3.4 diketonate structures coordinated to one rare earth element.

The rare earth element used in the present invention is trivalent and stably present. Therefore, 3.0 rare earth elements, ligand (a), ligand (b) and coordination can be obtained by coordination of 3.0 diketonate structures. The entire ligand (c) is neutralized in charge and constitutes a stable rare earth complex.

On the other hand, when the diketonate structure is coordinated in excess of 3.0, the rare earth element, the ligand (a), the ligand (b) and the ligand (c) as a whole are negatively charged. The rare earth complex of the present invention further has a counter cation.

Examples of the counter cation include at least one counter cation (d) selected from the group of counter cations represented by the following general formula (D).

In addition, the rare earth complex of the present invention has a specific rare earth element, a ligand (a), a ligand (b), and optionally a ligand (c), and these are the specific amounts described above. It is characterized by having. The ligand (a) constituting the rare earth complex of the present invention is a bis-diketonate having two diketonate structures, and the two diketonate structures may be coordinated to the same rare earth element or coordinated to different rare earth elements. You may rank. That is, since the rare earth complex of the present invention has a bisdiketonate structure, the type of rare earth element, the type of ligand (a), the ligand (b), the type of ligand (c), and the number per rare earth element are Even if it is the same, it can take various structures.

For example, the rare earth element is Eu, the ligand (a) is a ligand represented by the following general formula (a1), and there are 1.5 of these ligands per Eu, When the child (b) is phenanthroline, one phenanthroline is present per Eu, the ligand (c) is not present, and the 2α + γ is 3.0, the following general formula ( The rare earth complex represented by I) is conceivable. However, the rare earth complex of the present invention is not limited to the rare earth complex represented by the general formula (I), and is formed from the same rare earth element, a ligand, and the number of the ligand per rare earth element. Also included are rare earth complexes having other steric structures. Examples of the rare earth complex include a rare earth complex represented by the general formula (II) and a rare earth complex represented by the general formula (III).

In the examples of the present invention to be described later, the obtained rare earth complex is explained using a scheme, but it does not mean that only the rare earth complex represented by the general formula in the scheme was produced. The rare earth complex includes a rare earth complex represented by the general formula, and a rare earth complex having another steric structure formed from the same rare earth element, ligand, and number of the ligand per rare earth element. May contain. In addition, it is difficult to determine these structures exactly as one by a general analysis method and identification method.

The method for producing the rare earth complex of the present invention is not particularly limited. For example, it can be produced by the following method. The method for producing a rare earth complex of the present invention includes a compound that forms a ligand (a) by reacting and coordinating with a compound containing a rare earth element, and a compound that forms the ligand (b). The compound containing the rare earth element or the solution of the compound is added to the solution in which the compound that becomes the ligand (c) by reacting and coordinating with the compound containing is present as an optional component, and is reacted. The method of manufacturing a rare earth complex is mentioned.

In the method for producing a rare earth complex of the present invention, a compound that becomes a ligand (a) and a compound that becomes a ligand (c) are used by coordination with the compound containing the rare earth element.
Hydrate may be sufficient as the compound which comprises a ligand (b), and a compound containing rare earth elements.

Examples of the compound that becomes the ligand (a) by coordinating to the compound containing the rare earth element include at least one compound selected from the group of compounds represented by the following general formula (A ″). .

(In the general formula (A '') with the group of compounds represented, X ¹ and X ² are the same as X ¹ and X ² in the general formula (A).)
Examples of the compound that becomes the ligand (c) by coordinating with the compound containing the rare earth element include at least one compound selected from the group of compounds represented by the following general formula (C ″). .

The at least one compound selected from the compound group represented by the general formula (A ″) and the at least one compound selected from the compound group represented by the general formula (C ″) are so-called keto- Depending on the enol tautomerism, there may be a case where a diketone structure is taken, and a case where a structure consisting of a ketone and an enol is taken as shown in the formula, but in the present invention, the two are not particularly distinguished.

Examples of the compound constituting the ligand (b) include at least one compound selected from the group of compounds represented by the following general formula (B ″).

Examples of the rare earth element-containing compound include the rare earth element chlorides, bromides, acetates, oxides, and the like. The compound containing the rare earth element is preferably the chloride or bromide of the rare earth element described above.

Hereinafter, the method for producing the rare earth complex of the present invention will be described in more detail.
As an example of the method for producing the rare earth complex of the present invention, a compound that first becomes a ligand (a) by coordination with the compound containing the rare earth element, and a compound containing the rare earth element used as necessary The compound which becomes the ligand (c) by coordinating to is dissolved in a solvent to obtain a solution (i). Next, a base or an aqueous solution thereof is added to the solution (i), and then a compound constituting the ligand (b) is added to obtain a solution (ii). Next, a compound containing a rare earth element is added to the solution (ii) to obtain the rare earth complex of the present invention as a solid. Finally, the rare earth complex of the present invention can be produced by recovering the solid by an arbitrary method and purifying it as necessary.

As the solvent, an organic solvent or a mixed solvent of an organic solvent and water is usually used. As the organic solvent, a polar organic solvent is preferably used, and specific examples thereof include tetrahydrofuran (THF), ethanol, methanol, isopropyl alcohol, dioxane and the like.

Examples of the base include sodium hydroxide and triethylamine. As described above, the compound constituting the ligand (b) may be a hydrate.
The rare earth complex may be a hydrate as described above.

In addition, it is coordinated to the compound that forms the ligand (a) by coordinating to the compound containing the rare earth element, the compound constituting the ligand (b), and the compound containing the rare earth element used as necessary. The amount of the compound that becomes the ligand (c) by positioning depends on the amount of the ligand (a), ligand (b), and ligand (c) in the rare earth complex to be obtained. It is possible to select as appropriate.

The amount of the base used is usually in the range of a total amount to an excess amount of 2 times mole of the added ligand (a) and 1 time mole of the added ligand (c). Preferably, it is used in the range of a total amount of 1.5 times the total amount of 2 times mole of the added ligand (a) and 1 time mole of the added ligand (c).

In addition, when manufacturing the said rare earth complex by the said method, it is normally performed at room temperature and a normal pressure, However Heating, pressure reduction, pressurization, etc. may be performed as needed.
The use of the rare earth complex of the present invention will be described below.

Since the rare earth complex of the present invention absorbs ultraviolet light to blue light and emits light, it can be used as a light emitting material for various applications. Since the rare earth complex of the present invention is excellent in light resistance, it is preferably used as one of materials that constitute a solar cell module, for example, for applications exposed to light such as sunlight for a long period of time.

When using the rare earth complex of this invention, you may use for various uses as a resin composition containing the resin with the resin, ie, the rare earth complex of this invention, and resin.
As a method for producing the resin composition, the resin composition may be obtained by directly mixing or kneading the rare earth complex of the present invention with a resin, or a resin solution containing the rare earth complex of the present invention, a resin and a solvent. After the preparation, the resin composition may be obtained by removing the solvent.

The resin is not particularly limited, and examples thereof include polyvinyl acetal such as polyvinyl butyral, acrylic resin, polycarbonate, polystyrene, polyolefin, polyvinyl chloride, epoxy resin, fluororesin, and ethylene-vinyl acetate copolymer.

Examples of the solvent include chloroform, methylene chloride, toluene, THF, ethanol and the like.
The resin composition usually contains the rare earth complex of the present invention in an amount of 0.0001 to 30 parts by weight, preferably 0.0005 to 20 parts by weight, more preferably 100 parts by weight of the resin. 0.001 to 10 parts by mass is contained.

The resin solution usually contains 0.0001 to 30 parts by mass, preferably 0.0005 to 20 parts by mass, more preferably 0 to 100 parts by mass of the rare earth complex of the present invention. 001 to 10 parts by mass. The resin solution usually contains 100 to 100000 parts by mass, preferably 500 to 50000 parts by mass, and more preferably 1000 to 10000 parts by mass of the solvent with respect to 100 parts by mass of the resin.

Further, the resin composition and the resin solution may contain other additives. Examples of other additives include a plasticizer, an antioxidant, an ultraviolet absorber, a light stabilizer, a dehydrating agent, an adhesion adjusting agent, a silane coupling agent, a pigment, a crosslinkable monomer, and a polymerization initiator. The amount of these additives used varies depending on the application, but is usually in the range of 0.001 to 50 parts by mass with respect to 100 parts by mass of the resin.

Examples of the plasticizer include 3GO (triethylene glycol bis (2-ethylhexanoate)).
Applications of the rare earth complex of the present invention include a wavelength conversion sheet made of the resin composition and a sealant made of the resin composition.

The wavelength conversion sheet of the present invention comprises the resin composition. The wavelength conversion sheet of the present invention absorbs ultraviolet light to blue light, and crystalline silicon can be wavelength-converted to 550 to 1000 nm having high photoelectric conversion efficiency. By arranging the conversion sheet, it is possible to improve the power generation efficiency of the solar cell module.

The method for producing the wavelength conversion sheet is not particularly limited, but the method for producing the wavelength conversion sheet by applying the resin solution described above and removing the solvent, melt-kneading the resin composition, and extruding into a sheet form The method of manufacturing a wavelength conversion sheet by doing is mentioned.

The thickness of the wavelength conversion sheet of the present invention is usually 10 to 1000 μm.
The sealing agent of this invention consists of the said resin composition. The wavelength conversion sheet of the present invention absorbs ultraviolet light to blue light, and crystalline silicon can be wavelength-converted to 550 to 1000 nm having high photoelectric conversion efficiency. It is possible to improve the power generation efficiency of the solar cell module by containing the above-mentioned sealant.

The solar cell module of the present invention uses the wavelength conversion sheet and / or the sealant as one of its constituent members. The solar cell module of the present invention includes at least a solar cell and the wavelength conversion sheet, and the solar cell module in which the wavelength conversion sheet is disposed on the light receiving surface side of the solar cell, or at least a solar cell. Examples of the solar battery module include a cell, the sealing agent, and a front cover, and the sealing agent is contained between the solar battery cell and the front cover.

Conventionally known members can be used for each member such as a solar battery cell, a front cover, and a back cover that constitute the solar battery module of the present invention. Moreover, a well-known thing can be used suitably as members used for solar cell modules, such as an antireflection film.

EXAMPLES Next, although an Example is shown and this invention is demonstrated further in detail, this invention is not limited by these.
[Production Example 1]
(Synthesis of 4,4,5,5-Tetrafluor-3,8-dihydroxy-1,8-dithiophen-2-yl-octa-2,7-diene-1,6-dione (TTA-TTA))

In a 100 ml eggplant flask, sodium methoxide (1.30 g, 24.2 mmol) and ether (15 ml) were weighed and stirred in an ice bath. A mixed solution of dimethyl tetrafluorosuccinate (2.50 g, 11.5 mmol) and 2-acetylthiophene (1.45 g, 11.5 mmol) was slowly added dropwise thereto. After stirring at 0 ° C. for 20 minutes, an ether solution of 2-acetylthiophene (1.45 g, 11.5 mmol) was added dropwise, and the mixture was warmed to room temperature and stirred overnight. After the reaction, ether was distilled off under reduced pressure, water (30 ml) was added and the mixture was acidified with acetic acid, and the insoluble material was filtered off (Kiriyama filter paper No. 5C). The obtained solid was washed successively with water and ethanol and dried to obtain 3.14 g of the target product (TTA-TTA) as a pale yellow powder (yield 67%).

The 1H-NMR spectrum of the obtained target product was measured using an NMR measuring apparatus (Avance 400, manufactured by BRUKER).
1H-NMR (400 MHz, CDCl3): 7.84 (dd, J = 4.0, 1.2 Hz, 2H), 7.74 (dd, J = 4.8, 1.2 Hz, 2H), 7.20 (Dd, J = 4.8, 4.0 Hz, 2H), 6.51 (s, 2H).
[Comparative Example 1]
(Synthesis of Eu (TTA) 3Phen (Eu complex (c1)))

In a 500 ml eggplant flask, 4,4,4-trifluoro-1-thienyl-1,3-butanedione (TTA; 2.00 g, 9.00 mmol) was weighed and dissolved in ethanol (70 ml). Thereto, a 1M aqueous sodium hydroxide solution (11 ml, 11 mmol, 3.9 equivalents) and an ethanol solution (70 ml) of 1,10-phenanthroline monohydrate (668 mg, 3.37 mmol) were sequentially added at room temperature. After stirring for 1 hour, an aqueous solution (30 ml) of europium chloride hexahydrate (1.03 g, 2.81 mmol) was slowly added dropwise to form a precipitate. This was filtered off (Kiriyama filter paper No. 5C), washed with ethanol and dried to obtain 2.26 g of the desired product as a white powder (yield 81%).

The ¹ H-NMR spectrum of the obtained target product was measured using an NMR measuring apparatus (Avance 400, manufactured by BRUKER).
¹ H-NMR (400 MHz, CDCl ₃ ): 10.28 (bs, 2H), 10.19 (d, J = 7.8 Hz, 2H), 9.54 (s, 2H), 8.51 (d, J = 7.9 Hz, 2 Hz), 6.96 (d, J = 4.9 Hz, 3H), 6.50 (t, J = 4.0 Hz, 3H), 6.18 (s, 3H), 08 (s, 3H).
[Comparative Example 2]
(Synthesis of Eu complex (c2))

In a 200 ml eggplant flask, TTA-TTA (305 mg, 0.750 mmol) was weighed and dissolved in chloroform (50 ml).
Thereto, a methanol solution (5 ml) of europium chloride hexahydrate (183 mg, 0.500 mmol) and a methanol solution (2 ml) of triethylamine (151 mg, 1.50 mmol) were successively added dropwise at room temperature. After stirring for 1 hour, the generated precipitate was centrifuged, washed with chloroform, methanol, water and ether and dried to obtain 260 mg of a pale yellow powder (Eu complex (c2)) (yield 68%).

[Comparative Example 3]
(Synthesis of Eu complex (c3))

In a 50 ml eggplant flask, DBM-DBM (1,3-bis (3-phenyl-3-oxopropanoyl) benzene) (94.5 mg, 0.255 mmol) was weighed and dissolved in chloroform (8 ml).

Thereto, a methanol solution (2 ml) of europium chloride hexahydrate (62.3 mg, 0.170 mmol) and a methanol solution (2 ml) of triethylamine (52 mg, 0.51 mmol) were successively added dropwise at room temperature. After stirring for 1 hour, the produced precipitate was filtered off (Kiriyama filter paper No. 5C), washed with chloroform, methanol, water and ether, dried, and then 84.2 mg of yellow solid (Eu complex (c3)) was obtained. (Yield 70%).

In addition, using the Eu complex (c3), a 0.2% Eu complex-containing PVB sheet described in the section of light resistance evaluation described later was produced, but the sheet did not emit light even when irradiated with ultraviolet light. .

[Comparative Example 4]
(Synthesis of Eu complex (c4))

DBM-DBM (94.5 mg, 0.255 mmol) was weighed into a 50 ml eggplant flask and THF / ethanol / water (10/5/5 ml) was added.
Thereto, 1M aqueous sodium hydroxide solution (0.51 ml, 0.51 mmol) was added at room temperature, followed by ethanol solution (2 ml) of 1,10-phenanthroline monohydrate (33.7 mg, 0.170 mmol) and dissolved. I let you.

After stirring for 1 hour, an aqueous solution (2 ml) of europium chloride hexahydrate (62.3 mg, 0.170 mmol) was slowly added dropwise to produce a precipitate. This was centrifuged, washed with water and ethanol, dried, and 105 mg of a pale yellow powder (Eu complex (c4)) was obtained (yield 70%).

In addition, using the Eu complex (c4), a 0.2% Eu complex-containing PVB sheet described in the later section of light resistance evaluation was produced, but the sheet did not emit light even when irradiated with ultraviolet light. .

[Example 1]
(Synthesis of Eu complex (1))

To a 50 ml eggplant flask, TTA-TTA (305 mg, 0.750 mmol) was weighed, and THF / ethanol (15/8 ml) was added and dissolved.
Thereto, 1M aqueous sodium hydroxide solution (1.55 ml, 1.55 mmol) was added dropwise at room temperature, followed by ethanol solution (2 ml) of 1,10-phenanthroline monohydrate (99.1 mg, 0.500 mmol). .

After stirring for 10 minutes, an aqueous solution (2 ml) of europium chloride hexahydrate (183 mg, 0.500 mmol) was slowly added dropwise to produce a precipitate. After adding water, the precipitate was centrifuged, washed with ethanol and dried to obtain 298 mg of white powder (Eu complex (1)) (yield 63%).

[Example 2]
(Synthesis of Eu complex (2))

In a 50 ml eggplant flask, TTA (4,4,4-trifluoro-1-thienyl-1,3-butanedione) (111 mg, 0.500 mmol) and TTA-TTA (203 mg, 0.500 mmol) were weighed and THF was added. / Ethanol (8/10 ml).

Thereto, 1M aqueous sodium hydroxide solution (1.6 ml, 1.6 mmol) was added at room temperature, followed by ethanol solution (2 ml) of 1,10-phenanthroline monohydrate (99.1 mg, 0.500 mmol). .

After stirring for 10 minutes, an aqueous solution (2 ml) of europium chloride hexahydrate (183 mg, 0.500 mmol) was slowly added dropwise to produce a precipitate. After adding water, the precipitate was centrifuged, washed with ethanol, and dried to obtain 323 mg of white powder (Eu complex (2)) (yield 68%).

The following tests were conducted on the Eu complexes obtained in the examples and comparative examples.
[Measurement of current value of solar cell]
(Preparation of 0.02% Eu complex-containing PVB sheet)
In a 300 ml beaker, the Eu complex (1.3 mg) obtained in Examples and Comparative Examples was weighed and dissolved in 280 g of chloroform.

Thereto, 3GO (triethylene glycol bis (2-ethylhexanoate)) (2.43 g) and PVB (polyvinyl butyral) (6.38 g) were sequentially added and stirred at room temperature for 30 minutes.

The viscous solution obtained by stirring was spread on a Teflon (registered trademark) plate, and after removing volatile components overnight at room temperature, it was pressed at 120 ° C. and 15 MPa for 3 minutes with a small press machine manufactured by ASONE, about 0.3 mm thick A sheet containing 0.02% by mass of the Eu complex was prepared.

(Current value measurement)
Using the 300W solar simulator (NEWPORT ORIEL brand; 240W output, xenon lamp, AM1.5Direct filter), a pseudo-sunlight is brought into close contact with a crystalline Si solar cell (UCHIDA; output 1.5V, 400 mA). Was measured using a digital multimeter. The difference between the current value when the sheet (wavelength conversion film) was applied and when the sheet was not applied was measured, and the current increase value was obtained by subtracting the current value when the sheet was not applied from the current value when the sheet was applied.

(Light resistance evaluation)
(Preparation of PVB sheet containing 0.2% Eu complex)
In a 300 ml beaker, the Eu complex (12.8 mg) obtained in Examples and Comparative Examples was weighed and dissolved in 280 g of chloroform. Thereto, 3GO (2.43 g) and PVB (6.38 g) were sequentially added and stirred at room temperature for 30 minutes.

The viscous solution obtained by stirring was spread on a Teflon (registered trademark) plate, and after removing volatile components overnight at room temperature, it was pressed at 120 ° C. and 15 MPa for 3 minutes with a small press machine manufactured by ASONE, about 0.3 mm thick A sheet containing 0.2% by mass of the Eu complex was prepared.

(Light resistance test)
A laminated glass sample in which the above sheet is sandwiched between two slide glasses is prepared, and ultraviolet light is used using Super Xenon Weather Meter SX75 (manufactured by Suga Test Instruments Co., Ltd .; irradiation intensity: 180 W / m ² , black panel temperature 63 ° C.) Irradiation was performed. Before irradiating with ultraviolet light, 24 hours and 48 hours after irradiation with ultraviolet light, the above-mentioned sheet was irradiated with 366 nm ultraviolet light with a BLAK-RAY lamp (MODEL UVL-21). Measurement was performed with a photodetector (manufactured by Otsuka Electronics; Photo, MCPD-100, MCPD-3000).

[Comparative Example 5]
(Synthesis of Sm complex (c5))

In a 500 ml eggplant flask, 4,4,4-trifluoro-1-thienyl-1,3-butanedione (TTA; 711 mg, 3.20 mmol) was weighed and dissolved in ethanol (20 ml).

Thereto, a 1M aqueous sodium hydroxide solution (3.9 ml, 3.9 mmol) and an ethanol solution (7 ml) of 1,10-phenanthroline monohydrate (238 mg, 1.20 mmol) were sequentially added at room temperature.

After stirring for 10 minutes, an aqueous solution (4 ml) of samarium chloride hexahydrate (365 mg, 1.00 mmol) was slowly added dropwise to produce a precipitate. After adding water, the precipitate was centrifuged, washed with ethanol, and dried to obtain 944 mg of white powder (yield 95%).

The ¹ H-NMR spectrum of the obtained target product was measured using an NMR measuring apparatus (Avance 400, manufactured by BRUKER).
¹ H-NMR (400 MHz, CDCl3): 9.19 (br, 2H), 8.09 (d, J = 8.0 Hz, 2H), 7.77 (d, J = 3.6 Hz, 3H), 7 .58 (m, 2H), 7.52 (s, 2H), 7.47 (d, J = 4.8 Hz, 3H), 7.30 (s, 3H), 7.07 (t, J = 4) .0Hz, 3H).
Example 3
(Synthesis of Sm complex (3))

In a 100 ml eggplant flask, TFT (305 mg, 0.750 mmol) was weighed and THF / ethanol (15/15 ml) was added and dissolved.
Thereto, a 1M aqueous sodium hydroxide solution (1.55 ml, 1.55 mmol) was added dropwise at room temperature, followed by an ethanol solution (2 ml) of 1,10-phenanthroline monohydrate (99.1 mg, 0.500 mmol). .

After stirring for 10 minutes, an aqueous solution (2 ml) of samarium chloride hexahydrate (183 mg, 0.500 mmol) was slowly added dropwise to form a precipitate. After adding water, the precipitate was centrifuged, washed with ethanol and dried to obtain 284 mg of white powder (yield 61%).

Example 4
(Synthesis of Sm complex (4))

In a 100 ml eggplant flask, TTA (222 mg, 1.00 mmol) and TFT (406 mg, 1.00 mmol) were weighed and dissolved in THF / ethanol (16/20 ml).

Thereto, a 1M aqueous sodium hydroxide solution (3.1 ml, 3.10 mmol) was added at room temperature, followed by an ethanol solution (2 ml) of 1,10-phenanthroline monohydrate (198 mg, 1.00 mmol).

After stirring for 10 minutes, an aqueous solution (2 ml) of samarium chloride hexahydrate (365 mg, 1.00 mmol) was slowly added dropwise to produce a precipitate. After adding water, the precipitate was centrifuged, washed with ethanol and dried to obtain 927 mg of white powder (yield 97%).

The following tests were conducted on the Sm complexes obtained in the examples and comparative examples.
[Evaluation of light resistance]
When the powder (Sm complex) is irradiated with 350 nm light, the emission intensity at 610 nm is measured with Hitachi fluorescence spectrophotometer F-2700 for 10 minutes, and the initial emission intensity and the emission intensity after 10 minutes are connected. The slope of the straight line was obtained.

Light resistance was evaluated as the rate of decrease in emission intensity, that is, the magnitude of the inclination.
[Evaluation of heat resistance]
After heating 10 mg of the powder (Sm complex) at 200 ° C. for 15 minutes, the fluorescence intensity at 605 nm when irradiated with 350 nm light was measured with a Hitachi fluorescence spectrophotometer F-2700. The fluorescence intensity was measured under the same conditions before heating.

The heat resistance was evaluated as the presence or absence of strength reduction before and after heating.
[Measurement of current value of solar cell]
(Preparation of PVB sheet containing 0.2% Sm complex)
In a 300 ml beaker, the Sm complexes (12.8 mg) obtained in Examples and Comparative Examples were weighed and dissolved in 280 g of chloroform (ultrasonic dispersion).

Thereto, 3GO (2.43 g) and PVB (6.38 g) were sequentially added and stirred at room temperature for 30 minutes.
The viscous solution obtained by stirring was spread on a Teflon (registered trademark) plate, volatile components were removed overnight at room temperature, and then pressed at 120 ° C. and 15 MPa for 3 minutes with a small press machine. A sheet containing 0.2% by mass of the complex was produced.

(Preparation of PVB sheet)
To 280 g of chloroform, 3GO (2.43 g) and PVB (6.38 g) were sequentially added and stirred at room temperature for 30 minutes.

The viscous solution obtained by stirring was spread on a Teflon (registered trademark) plate, volatile components were removed overnight at room temperature, and then pressed at 120 ° C. and 15 MPa for 3 minutes with a small press machine. Was made.

(Current value measurement)
Using the 300W solar simulator (NEWPORT ORIEL brand; 240W output, xenon lamp, AM1.5Direct filter), a pseudo-sunlight is brought into close contact with a crystalline Si solar cell (UCHIDA; output 1.5V, 400 mA). Was measured using a digital multimeter. The electric current value at the time of sticking a sheet (wavelength conversion film) (PVB sheet or PVB sheet containing 0.2% Sm complex) was measured.

The Sm complexes (3) and (4) obtained in the examples are superior in light resistance and heat resistance as compared to the Sm complex (c5) obtained in the comparative example. Moreover, the current value increased by using the Sm complex.

Claims

A complex comprising at least one rare earth element selected from Pr, Eu, Sm, Tb, Dy, Ho, and Er,
At least one ligand (a) selected from the ligand group represented by the following general formula (A) is coordinated with the rare earth element in an amount of 0.8 to 1.7 per rare earth element. And
At least one ligand (b) selected from the ligand group represented by the following general formula (B) is coordinated with 0.8 to 1.2 of the rare earth element per rare earth element. And
At least one ligand (c) selected from the ligand group represented by the following general formula (C) is coordinated to the rare earth element in an amount of 0 to 1.4 per rare earth element. ,
Rare earth complex characterized in that 2α + γ is 3.0 to 3.4, where α is the number of ligands (a) per rare earth element and γ is the number of ligands (c). .

(In the ligand group represented by the general formula (A), X 1 and X 2 are each independently an aromatic ring, a heteroaromatic ring, —C (CH 3 ) 3 , —CH 3 , —CF 3 , — C 2 F 5 , —C 3 F 7 , or —C 4 F 9. )
The rare earth complex according to claim 1, comprising at least one rare earth element selected from Eu, Sm and Tb.
The rare earth complex according to claim 1 or 2, wherein 2α + γ is 3.0.
A resin composition comprising the rare earth complex according to any one of claims 1 to 3 and a resin.
A resin solution comprising the rare earth complex according to any one of claims 1 to 3, a resin and a solvent.
A wavelength conversion sheet comprising the resin composition according to claim 4.
A sealant comprising the resin composition according to claim 4.
Having at least solar cells and the wavelength conversion sheet according to claim 6;
The solar cell module, wherein the wavelength conversion sheet is disposed on a light receiving surface side of the solar cell.
At least a solar battery cell, the sealant according to claim 7, and a front cover,
The solar cell module comprising the sealing agent between the solar cell and a front cover.